Blower and heater unit

ABSTRACT

An integrated heater and blower unit has a housing formed by complementary upper and lower shells of synthetic resin abutting at juxtaposed edges and jointly forming a housing defining a spaced closed at the rear and both sides and open at the front. A transverse flow blower is arranged at the closed rear of the housing for establishing a flow of air inwardly through the lower portion of the open front and outwardly through the top portion of the open front. Selectively energized electric heating elements are arranged within the housing for heating the outwardly flowing air. The internal configuration of the shells is such that all constituent parts, component parts or components of the unit can be quickly positioned therein without use of additional fasteners. The arrangement of parts inside the shells is such as to minimize the bulk of the unit.

United States Patent 1191 Glucksman BLOWER AND HEATER UNIT Inventor: Dov Z. Glucksman, Newton Centre,

Mass.

Assignee: Intermatic Incorporated, Spring Grove, 111.

Filed: Oct. 22, 1971 Appl. No.: 191,820

Related US. Application Data Continuation of Ser. No. 88,268, Nov. 10, 1970, abandoned.

[56] References Cited UNITED STATES PATENTS 11/1963 Braun et a1. 219/370 X 9/1964 Walker 415/54 UX 11/1965 Laing 415/54 7/1966 Laing 219/370 X 5/1967 Laing 219/370 Nov. 5, 1974 3,415,314 12/1968 Jackson et a1. 165/122 FOREIGN PATENTS OR APPLICATIONS 1,117,898 6/1968 Great Britain 219/370 Primary Examiner-A. Bartis Attorney, Agent, or Firm-Hill, Gross, Simpson, Van Santen, Steadman, Chiara & Simpson [57] ABSTRACT An integrated heater and blower unit has a housing formed by complementary upper and lower shells of synthetic resin abutting at juxtaposed edges and jointly forming a housing defining a spaced closed at the rear and both sides and open at the front. A transverse flow blower is arranged at the closed rear of the housing for establishing a flow of air inwardly through the lower portion of the open front and outwardly through the top portion of the open front. Selectively energized electric heating elements are arranged within the housing for heating the outwardly flowing air. The internal configuration of the shells is such that all constituent parts, component parts or components of the unit can be quickly positioned therein without use of additional fasteners. The arrangement of parts inside the shells is such as to minimize the bulk of the unit.

7 Claims, 14 Drawing Figures LJLJLILILILIL] )(JLILIL PMENTEDRUV 51914 I S'MGN mm m a PATENIED 5U? IBM l 7 WEE? Q 1 BLOWER AND HEATER UNIT This application is a continuation of my application Ser. No. 88,268, filed Nov. 10, 1970 and now abandoned.

BACKGROUND OF INVENTION Integrated blower and heater units should be as compact as possible and it should be possible to assemble the numerous constituent parts or components thereof within a minimum of time, with little effort, and with a minimum of additional fasteners. Prior art units of the kind under consideration do not sufficiently comply with these basic requirements. The present invention makes it possible to achieve a drastic reduction of the size of blower and heater units, and to drastically reduce the time and cost involved in the assembly of the constituent parts, or components, thereof.

SUMMARY OF THE INVENTION Integrated heater and blower units embodying this invention include an upper shell of synthetic resin and a lower shell of synthetic resin abutting at juxtaposed edges thereof and jointly forming a housing defining a space closed at the rear and at both sides and open at the front thereof. Stud means projecting through said lower shell into said upper shell clamp the upper shell against the lower shell. A bladed substantially cylindrical transverse flow blower rotor supported by shaft means is arranged at the closed rear of said housing. An electromotor including a stator and a rotor is arranged within said housing in coaxial relation with said blower rotor for driving said blower rotor. A plurality of electric heater resistors are arranged within said housing adjacent the open front thereof for heating the flow of air established by said blower rotor. Said plurality of heater resistors are supported by a frame structure arranged within said housing. Arranged within said housing is further a control switch for controlling said electromotor and said plurality of heater resistors. Said upper shell and said lower shell each include one of a pair of internal partitions arranged in a common plane at right angles to said shaft means of said blower rotor and supporting the end of said shaft means remote from said electromotor. Said upper shell and said lower shell each define one of a pair of grooves arranged in a common plane adjacent to said open front of said housing. Said lower shell is provided with perforations at the region thereof juxtaposed to said blower rotor forming an air intake for said blower rotor. At least said lower shell includes internal projections engaging said stator of said electromotor for positioning said electromotor and internal projections engaging said frame structure supporting said plurality of heater resistors for positioning said frame structure and said plurality of heater resistors. A perforated plate forming a combined control panel and air discharge grille has edges projecting into said pair of grooves defined by said upper shell and said lower shell and closing the open front of said housing.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a bottom plan view of an upper shell for forming a housing;

FIG. 2 is a section along 2-2 of FIG. 1;

FIG. 3 is a section along 3-3 of FIG. 1;

FIG. 4 is a section along 4-4 of FIG. 1;

FIG. 5 is a top plan view of a shell complementary to that shown in FIGS. I-4;

FIG. 6 is a section along 6-6 of FIG. 5;

FIG. 7 is a section along 7-7 of FIG. 5;

FIG. 8 is a section along 8-8 of FIG. 5;

FIG. 9 is a front elevation of a complete structure embodying this invention;

FIG. 10 is a top plan view of a structure embodying this invention i.e., the structure of FIG. 9 upon removal of the upper housing shell thereof and breaking away in part the frame structure for supporting the heating elements;

FIG. 11 is a section along 11-11 of FIG. 10;

FIG. 12 is a wiring diagram of the structure illustrated in FIGS. 1-11;

FIG. 13 is a section along 13-13 of FIG. 14 showing the structure on a larger scale; and

FIG. 14 is a section along 14-14 of FIG. 10.

DESCRIPTION OF PREFERRED EMBODIMENT The components of the blower and heater structure are enclosed in a housing including an upper shell 1 of synthetic resin and a complementary lower shell 2 of a synthetic resin jointly forming the housing 1,2. Housing 1,2 defines a space closed at the rear R, and at both sides S, and open at the front F. Upper shell 1 is provided with four bosses 11 and lower shell 2 is provided with four bosses 21. Bosses 11 and 21 are in registry when the upper shell 1 is superimposed upon the lower shell 2. Bosses 11 and 21 define passageways for stud means 500 (FIG. 11) projecting through lower shell 2 into the upper shell 1 for clamping the upper shell 1 against the lower shell 2. Preferably the bosses 21 in lower shell 2 form passageways open on both ends thereof, while the bosses 11 in upper shell 1 form passageways open at the ends thereof adjacent lower shell 2, and closed at the ends thereof remote from lower shell 2. This makes it possible to insert self-tapping screws 500 into the passages defined by bosses 21, and to form screw-threads by screws 500 in the passages defined by bosses 11. When shells l and 2 are superimposed their juxtaposed edges are in abutting engagement. Then the projections 12 of upper shell 1 engage, and are guided by, the internal surface of lower shell 2. To be more specific, the three projections 12 arranged along the long side of upper shell 1 engage juxtaposed recesses 22 in lower shell 2, and the three projections 12 arranged along each of the short sides of upper shell 1 engage directly the internal surface of lower shell 2.

Referring now more particularly to FIGS. 10 and 11, the housing 1,2 formed by the two complementary shells l and 2 houses a substantially cylindrical transverse flow blower rotor 3 supported by shaft means, i.e., two shaft sections 4 and arranged at the closed rear R of housing 1,2. The transverse flow blower rotor 3 includes axially extending blades and ends 33 each formed by a circular blade-supporting rim and three spiders which form hubs at the radially inner ends thereof (FIG. 11). Reference character 5 has been applied to generally indicate an electromotor for driving blower rotor 3. Electric motor 5 includes a stator 51 supporting an energizing winding 52, and it further includes a rotor 53 arranged in coaxial relation with blower rotor 3. The shaft of rotor 53 arranged in coaxial relation with blower rotor 3. The shaft of rotor 53 of motor 5 forms one of the above referred-to shaft sections 4 Supporting blower rotor 3. To be more specific, the shaft of rotor 53 is fixedly coupled with one of the aforementioned ends 33 of blower rotor 3 so that blower rotor 3 rotates jointly with the motor rotor 53. The electromotor 5 has a pair of bearings 54 for the shaft thereof of which one supports the adjacent end of blower rotor 3.

The temperature of electromotor 5 is generally higher than the temperature of the air transported by blower rotor 3. Due to the presence of spiders in the ends 33 of blower rotor 3 a flow of cooling air away from motor 5 is established by the rotation of blower rotor 3.

Housing 1,2 further houses a plurality of heater resistors 6 which may consist of helically wound wire. These heater resistors 6 have been diagrammatically indicated .in FIGS. and 11. Resistors 6 are arranged within housing 1,2 adjacent the open front F thereof for heating the flow of air established by blower rotor 3. These resistors are supported by a box-like frame structure 7 of sheet metal and are electrically insulated from the latter by insulating bushings 8 supported by frame structure 7. Frame structure 7 includes a slanting tablike projection 71 which forms a cut-off for the air flow produced by blower rotor 3, and frame structure 7 further forms a pair of tab-like projections 72 extending toward lower shell 2 and engaging lowershell 2 in order to support resistors 6 by lower shell 2. How this is achieved will be explained below more in detail.

Reference numeral 9 has been applied to indicate a control switch arranged within housing 1,2 for controlling electromotor 5 and said plurality of heater resistors 6. Control switch 9 includes a plurality of push buttons 91.

The upper shell 1 is provided with a partition 13 and the lower shell 2'is provided with a partition 23 which are arranged in a common plane at right angles to the line defined by shaft sections 4. The internal partitions 13,23 support the shaft section 4 remote from electromotor 5. To this end partitions 13 and 23 are provided with semi-circular cut-outs 13' and 23, respectively. Cut-outs l3,23 receive a rubber disc 101 for supporting the axially outer end of shaft section 4 remote from electromotor 5. This precludes transmission of 'vibrations of blower rotor 3 to housing 1,2. Rubber disc 101 may be provided with a circumferential groove into which the semicircular edges of cut-outs l3',23' may project, and rubber disc 101 may be provided with a metal sleeve at the center thereof forming a bearing for shaft section 4 remote from motor 5.

Partitions 13 and 23 form also a lateral surface for a housing for transverse flow blower rotor 3. Shells 1,2 form other portions of the blower housing. The upper shell 1 is further provided with ,a partition 14 parallel to partition 13 and forming a lateral surface for a blower housing. There is no partition in lower shell 2 corresponding to the partition 14 in upper shell 1. Provision of such a partition has been dispensed with in order to make it possible for blower rotor 3 to cool electromotor 5 by flows of heated air away from the latter into the former through one of the perforated ends 33 thereof. To achieve this object the space between motor 5 and blower rotor 3 must be substantially unobstructed by shell 2.

Upper shell 1 forms a groove 15 and lower shell 2 forms a groove 24. Grooves l5 and 24 are arranged in a common plane adjacent the open front of the housing I formed by joining shells 1 and 2.

Lower shell 2, is provided with perforations 25 form- I ing an air inlet grille. The perforated region of lower shell 2 is juxtaposed to blower rotor 3.

The lower shell 2 and the upper shell 1 include internal projections engaging the stator 51 of electromotor 5. and positioning the latter inside of housing 1.2. These projections include a rib 25, two ribs 26 intersecting rib 25 at right angles, and four uprights 27. Ribs 25,26 form a support for stator 51 of motor 5, and the uprights 27 are intended to engage the lateral surfaces of stator 51 of motors 5. In like fashion the upper shell 1 is provided with internal projections which include ribs 16 and 17 arranged at right angles, and cylindrical projections 18. Ribs 16,17 form a bed for the upper end surface 55 of the stator 51 of electromotor 5, and the cylindrical projections 18 are intended to overlap the lateral surfaces of stator 51 at right angles to the end surfaces 55 thereof. It is thus apparent that the stator 51 of motor 5 is supported on the upper side and on the lower side thereof in substantially the same fashion, i.e., by ribs engaging the end surfaces 55 of the stator 51 and by projections protruding beyond the ribs and engaging the lateral surfaces of the stator. This duplication of positioning means for the stator 51 of motor 5 in the lower shell 2 and in the upper shell 1 is highly desirable to achieve a high degree of precision in positioning motor 5. Other kinds of motor positioning means might, however, be substituted for the projections in the upper shell 1.

The prismatic control switch 9 is positioned by positioning means similar to those used for positioning electromotor 5. To be morespecific, ribs 28 which intersect at right angles and are an integral part of lower shell 2 form a support for the base or lower end surface of control switch 9 and three pins 28 which project beyond ribs 28 are intended to engage the side surfaces of prismatic control switch 9. The ribs 16' which intersect at right angles and are an integral part of upper shell 1 form a support abutting against the top surface 92 of control switch 9, and the three pins 17 which project beyond ribs 16 are intended to engage the side surfaces, or lateral surfaces, of control switch 9. This duplication of positioning means for control switch 9 in the lower shell 2 and in the upper shell 1 is highly desirable to achieve a high degree of precision in positioning control switch 9. The projections 16,l7 in the upper shell 1 might, however, be replaced by other kinds of control switch positioning means.

Reference numeral 111 has been applied to indicate a perforated plate forming a combined control panel and air discharge grille. As shown in FIGS. 9 and 11 one portion of plate 111 has perforations for the passage of push buttons 91 of control switch 9, and another portion 112 of plate 111 has a large number of small perforations intended to form an air discharge grille. In FIG. 9 the small perforations in the center region of plate or panel 111 have been deleted for reasons of greater simplicity. The peripheral edges of plate 111 project into the grooves 24 of lower shell 2, and into the grooveslS of upper shell 1. Thus plate or panel 111 is firmly heldin position and closes the open front F of housing 1,2.

Control switch '9 might be a rotary switch, but the multi-push-button switch shown in FIGS. 9-11 is preferred. A rotary control switch could readily be supported by panel 111, but a push button switch of prismatic shape cells for the support means 28, 28', and preferably the additional support means 16,17'.

The lower shell 2 has four internal partitions 26',27' defining a prismatic space. Two of the aforementioned partitions, i.e., partitions 26 are relatively long, and two of the aforementioned partitions, i.e., partitions 27, are relatively short (FIG. 5). The length of partitions 26 is substantially equal to the length of blower rotor 3, and they extend parallel to the axis of blower rotor 3, or parallel to parts 4. Partitions 26 and 27' are arranged at right angles. There is an aperture 28" in the lower shell 2 midway between partitions 27' for the passage of a thermostabadjusting-knob 211. As shown in FIGS. and 11 a thermostat 311 is arranged in the space bounded by the ribs or partitions 26',27' of lower shell 2. The object of thermostat 311 is to automatically de-energize electromotor 5 and resistors 6 when the ambient temperature has reached, or exceeds, a predetermined level. The tabs 72 forming part of the frame structure 7 supporting heater resistors 6 engage the axially inner surfaces of partitions 27', as a result of which parts 6 and 7 are positioned and supported by lower shell 2. It will be apparent from FIGS. 10 and 11 that tab 71 projects in cantilever fashion from frame structure 7 of which it forms a part, and it will also be apparent from the aforementioned figures that the lateral edges of tab 71 juxtaposed to the lateral walls of housing shells 1,2 are spaced from and hence unsupported by the lateral walls of housing shells 1,2. FIGS. 10 and 11 further show that tab 71 is formed by one single bend in a horizontal plate forming part of frame structure 7, and that the portion of tab 71 closest to the transverse flow blower rotor 3 is a free exposed edge. Thus tab 71 forms a cut-off of extreme simplicity whose cost of manufacture are minimal.

The rear ends of upper shell I and lower shell 2 are curved convexly, and both shells 1,2 form at the rear a sharp edge at the line of engagement thereof (FIG. 11). The lower shell 2 is provided with a pair of external shell-supporting ribs 29 forming an integral part thereof, and projecting at right angles from the surface thereof. Each of said pair of shell-supporting ribs 29 has a pair of rib-supporting edges 29' and 29" imparting two stable positions to lower shell 2-and to the entire structure supported by the same-when resting on a horizontal plane by means of said rib-supporting edges 29,29. Rib-supporting edges 29',29" are oriented to impart to said combined control panel and air discharge grille 111 a relatively slight rearward slant when said lower shell 2 rests on a horizontal plane on one of said pair of rib-supporting edges 29, and to impart to said combined control panel and air discharge grille 111 a relatively large rearward slant when said lower shell 2 rests on a horizontal plane on the other of said pair of rib-supporting edges 29" of said shellsupporting ribs 29. In the first mentioned position the unit may be used both as a room heater, and a foot warmer. In the second more elevated position the unit may be used as a hair dryer and desk top fan. The unit is further adapted to be used as a window defogger or defroster, particularly for defogging or defrosting large picture windows. To this end each of shell-supporting ribs 29 is provided with a third rib-supporting edge 29" which ends right at the rear edge formed between lower shell 2 and upper shell 1 (FIG. 11). When the unit is supported on a horizontal plane by ribsupporting edges 29", i.e., in the most upright position thereof, it is capable of producing blasts of hot air which are directed upwards at a steep angle of almost degrees, as needed for defogging, or defrosting, windows.

The assembly of a unit as shown in FIGS. 1-1l from its components may be achieved within a few minutes. The assembly is started by placing all internal parts or components in position in lower shell 2. Thercupon the upper shell 1 is mounted on the lower shell 2 so that all parts or components are firmly clamped between shells l and 2, and cannot move out of their respective position.

In the diagram of FIG. 12 the same reference characters as in FIGS. 1-11 have been applied to indicate like parts, however, FIG. 12 shows a rotary control switch 9 rather than the push button control switch 9 shown in FIGS. 1-11. Both types of switches are performing the same switching operations. In the first position of control switch 9 the unit is de-energized, in the second position of control switch 9 motor 5 is energized and all resistors 6 de-energized, in the third position of control switch 9 two serially connected resistors 6 and motor 5 are energized and in the fourth position of control switch 9 two pairs of serially connected resistors 6 and motor 5 are energized.

The leads for energizing the components of the blower and heater unit are brought into housing 1,2 by means of a grommet (FIG, 10).

The internal projections in lower shell 2 and in upper shell 1 for positioning stator 51 have two different levels (see particularly FIGS. 13 and 14). The low level portions or fins 25,26 of lower shell 2 are intended to engage, and engage, the lower end surface 55 of stator 51, and the pin-like high level portions 27 oflower shell 2 are intended to engage, and engage, the lateral surfaces of stator 51 which are at right angles to the end surfaces of stator 51. The fin-like or rib-like low level portions 16,17 of upper shell 1 are intended to engage, and engage, the upper end surface 55 of stator 51, and the pin-like high level portions 18 of upper shell 1 are intended to engage, and engage, the lateral surfaces of stator 51 at right angles to the end surfaces 55 thereof. The internal projections in shells 1 and 2 for position ing control switch 9 have also two different levels. The fin-like or rib-like low level projections 28 of lower shell 2 are intended to engage, and engage, the lower end surface 92 of control switch 9, and the pin-like high level projections 28 of lower shell 2 are intended to engage, and engage, the lateral surfaces of control switch 9 at right angles to the end surfaces 92 thereof. The finlike or rib-like low level projections 16', of upper shell 1 are intended to engage or abut against the upper end surface 92 of control switch 9, and the pin-like high level projections 17' of upper shell 1 are intended to engage, and engage, the lateral surfaces of control switch 9 at right angles to the end surfaces 92 thereof.

FIGS. 13 and 14 show on a relatively large scale how electromotor 5 is positioned inside of the space bounded by shells 1 and 2. It will be apparent from the above that control switch 9 is positioned within said space in substantially the same way as electromotor 5.

I claim as my invention:

A blower and heater unit including c a bladed substantially cylindrical transverse flow blower rotor supported by shaft means and arranged at said closed rear of said housing,an electromotor including a stator and a rotor arranged within .said housing in coaxial relation to said blower rotor for driving said blower rotor, a plurality of electric heater resistors arranged within said Y housing adjacent said open front thereof for heating the flow of air established by said blower rotor, a frame structure arranged within said housing supporting said plurality of heater resistors and a control switch arranged within said housing for controlling said electromotor and said plurality of heater resistors;

I d. said upper shell and said lower shell each including one of a pair of internal partitions arranged in a common plane at right angles to said shaft means of said blower rotor and supporting the end of said shaft means remote from said electromotor, said upper shell and said lower shell each defining one of a pair of grooves arranged in a common plane adjacent said open front of said housing, said lower shell being provided with perforations at the region thereof juxtaposed to said blower rotor forming an air intake for said blower rotor, and at least said lower shell including internal projections engaging said vstator of said electromotor for positioning said electromotor and internal projections engaging said frame structure supporting said plurality of heater resistors for positioning said frame structure and said plurality of heater resistors; and

e a perforated plate forming a combined control panel and air discharge grille having edges projecting into said pair of grooves defined by said upper shell and said lower shell and closing said open front of said housing.

2. A unit as specified in claim 1 wherein a said control switch is a multi-push-button switch projecting with the push-buttons thereof through openings in said combined control panel and air discharge grille;

b said lower shell and said upper shell are each provided with internal projections engaging said pushbutton switch for positioning said push-button switch; and wherein c said lower shell and said upper shell are each provided with said internal projections engaging said stator of said electromotor for positioning said electromotor.

3. A unit as specified in claim 1 wherein a said upper shell is provided with a partition projecting into the space between one end of said blower rotor and said electromotor and forming one side of a blower housing;

b the space between said electromotor and said blower rotor is substantially unobstructed by said lower shell to allow cooling of said electromotor by currents of air established by the operation of said blower rotor; and wherein .c said frame structure supporting said plurality of heater resistors is provided with a tab like extension forming a cut-off for the air flow produced by said blower rotor.

4. A unitias specified in claim 1 wherein a said lower shell is provided with a pair of external shellsupporting ribs projecting at right angles from the surface thereof, each of said pair of shellsupporting ribs having a pair of rib-supporting edges enclosing an obtuse angle andimparting two stable positions to said lower shell when resting on a horizontal plane by means of one of said pair of rib-supporting edges of each of said pair of shel|- supporting ribs, said pair of rib-supporting edges being oriented to impart to said combined control panel and air discharge grille a relatively slight rearward slant when said lower shell rests on a horizontal plane on one of said pair of rib-supporting edges of said shell-supporting ribs, and to impart to said combined control panel and air discharge grille a relatively large rearward slant when said lower shell rests on a horizontal plane on the other of said pair of rib-supporting edges of said shellsupporting ribs.

5. A unit as specified in claim 1 wherein a said lower shell has four internal partitions defining a prismatic space having a pair of relatively long sides substantially equal in length to said blower rotor extending parallel to the axis of said blower rotor and a pair of relatively short sides each arranged at right angles to said pair of relatively long sides;

b a thermostat having a regulating knob is arranged inside said prismatic space;

c said lower shell is provided within an aperture for the passage of said regulating knob to the outside of said lower shell; and wherein d said frame structure of said plurality of heater resistors is provided with a pair of tab-like projections entering into prismatic space and positioned therein by said four internal partitions of said lower shell,

6. A unit as specified in claim 2 wherein a said internal projections engaging said multi-pushbutton switch have two different levels including lower level portions for engaging end surfaces of said push-button switch and including higher level portions for engaging lateral surfaces of said push- 1 button switch at right angles to said end surfaces thereof; and wherein b said internal projections engaging said stator of said electromotor include lower level portions for engaging end surfaces of said stator and higher level portions for engaging lateral surfaces of said stator at right angles to said end surfaces thereof.

7. A blower and heater unit including a a housing having an upper shell and a lower shell and defining an intake opening and an exhaust opening;

b a bladed substantially cylindrical transverse flow blower rotor supported by shaft means and arranged inside said housing adjacent said intake opening thereof, an electromotor including a stator and a rotor arranged within said housing in coaxial relation to said blower rotor for driving said blower rotor, electric heater resistors arranged within said housing adjacent saidexhaust opening thereof for 9 10 heating the flow of air established by said blower tions within said housing adjacent and parallel to rotor, a frame structure arranged within said housthe end surfaces of said blower rotor, and said air ing between said exhaust opening thereof and said flow guiding means further including portions of blower motor forming a passageway for said flow the wall of said housing; and of air and supporting said heater resistors, positiond a relatively short substantially planar tab-like exing means at least on the bottom of said lower shell tension on said frame structure formed by a single for positioning said frame structure inside said bend therein and projecting in cantilever fashion housing, and a control switch arranged within said from said frame structure toward said transverse housing for controlling said electromotor and said flow blower and having a free exposed edge thereof heater resistors; near to said transverse flow blower and forming a c means for guiding said air flow from said intake cut-off for the air flow produced by said transverse opening of said housing to said exhaust opening flow blower. I thereof, said air flow guiding means including parti- 

1. A blower and heater unit including a an upper shell of a synthetic resin and a lower complementary shell of a synthetic resin abutting at juxtaposed edges thereof and jointly forming a housing defining a space closed at the rear and at both sides and open at the front thereof; b stud means projecting through said lower shell into said upper shell for clamping said upper shell against said lower shell; c a bladed substantially cylindrical transverse flow blower rotor supported by shaft means and arranged at said closed rear of said housing, an electromotor including a stator and a rotor arranged within said housing in coaxial relation to said blower rotor for driving said blower rotor, a plurality of electric heater resistors arranged within said housing adjacent said open front thereof for heating the flow of air established by said blower rotor, a frame structure arranged within said housing supporting said plurality of heater resistors and a control switch arranged within said housing for controlling said electromotor and said plurality of heater resistors; d said upper shell and said lower shell each including one of a pair of internal partitions arranged in a common plane at right angles to said shaft means of said blower rotor and supporting the end of said shaft means remote from said electromotor, said upper shell and said lower shell each defining one of a pair of grooves arranged in a common plane adjacent said open front of said housing, said lower shell being provided with perforations at the region thereof juxtaposed to said blower rotor forming an air intake for said blower rotor, and at least said lower shell including internal projections engaging said Stator of said electromotor for positioning said electromotor and internal projections engaging said frame structure supporting said plurality of heater resistors for positioning said frame structure and said plurality of heater resistors; and e a perforated plate forming a combined control panel and air discharge grille having edges projecting into said pair of grooves defined by said upper shell and said lower shell and closing said open front of said housing.
 2. A unit as specified in claim 1 wherein a said control switch is a multi-push-button switch projecting with the push-buttons thereof through openings in said combined control panel and air discharge grille; b said lower shell and said upper shell are each provided with internal projections engaging said push-button switch for positioning said push-button switch; and wherein c said lower shell and said upper shell are each provided with said internal projections engaging said stator of said electromotor for positioning said electromotor.
 3. A unit as specified in claim 1 wherein a said upper shell is provided with a partition projecting into the space between one end of said blower rotor and said electromotor and forming one side of a blower housing; b the space between said electromotor and said blower rotor is substantially unobstructed by said lower shell to allow cooling of said electromotor by currents of air established by the operation of said blower rotor; and wherein c said frame structure supporting said plurality of heater resistors is provided with a tab-like extension forming a cut-off for the air flow produced by said blower rotor.
 4. A unit as specified in claim 1 wherein a said lower shell is provided with a pair of external shellsupporting ribs projecting at right angles from the surface thereof, each of said pair of shell-supporting ribs having a pair of rib-supporting edges enclosing an obtuse angle and imparting two stable positions to said lower shell when resting on a horizontal plane by means of one of said pair of rib-supporting edges of each of said pair of shell-supporting ribs, said pair of rib-supporting edges being oriented to impart to said combined control panel and air discharge grille a relatively slight rearward slant when said lower shell rests on a horizontal plane on one of said pair of rib-supporting edges of said shell-supporting ribs, and to impart to said combined control panel and air discharge grille a relatively large rearward slant when said lower shell rests on a horizontal plane on the other of said pair of rib-supporting edges of said shell-supporting ribs.
 5. A unit as specified in claim 1 wherein a said lower shell has four internal partitions defining a prismatic space having a pair of relatively long sides substantially equal in length to said blower rotor extending parallel to the axis of said blower rotor and a pair of relatively short sides each arranged at right angles to said pair of relatively long sides; b a thermostat having a regulating knob is arranged inside said prismatic space; c said lower shell is provided within an aperture for the passage of said regulating knob to the outside of said lower shell; and wherein d said frame structure of said plurality of heater resistors is provided with a pair of tab-like projections entering into prismatic space and positioned therein by said four internal partitions of said lower shell.
 6. A unit as specified in claim 2 wherein a said internal projections engaging said multi-push-button switch have two different levels including lower level portions for engaging end surfaces of said push-button switch and including higher level portions for engaging lateral surfaces of said push-button switch at right angles to said end surfaces thereof; and wherein b said internal projections engaging said stator of said electromotor include lower level portions for engaging end surfaces of said stator and higher level portions for engaging lateral surfAces of said stator at right angles to said end surfaces thereof.
 7. A blower and heater unit including a a housing having an upper shell and a lower shell and defining an intake opening and an exhaust opening; b a bladed substantially cylindrical transverse flow blower rotor supported by shaft means and arranged inside said housing adjacent said intake opening thereof, an electromotor including a stator and a rotor arranged within said housing in coaxial relation to said blower rotor for driving said blower rotor, electric heater resistors arranged within said housing adjacent said exhaust opening thereof for heating the flow of air established by said blower rotor, a frame structure arranged within said housing between said exhaust opening thereof and said blower motor forming a passageway for said flow of air and supporting said heater resistors, positioning means at least on the bottom of said lower shell for positioning said frame structure inside said housing, and a control switch arranged within said housing for controlling said electromotor and said heater resistors; c means for guiding said air flow from said intake opening of said housing to said exhaust opening thereof, said air flow guiding means including partitions within said housing adjacent and parallel to the end surfaces of said blower rotor, and said air flow guiding means further including portions of the wall of said housing; and d a relatively short substantially planar tab-like extension on said frame structure formed by a single bend therein and projecting in cantilever fashion from said frame structure toward said transverse flow blower and having a free exposed edge thereof near to said transverse flow blower and forming a cut-off for the air flow produced by said transverse flow blower. 